Screw-wrench.



No. 716,303; Pafented Dec. "3,1902;

L. S. STARRETT.

SCREW WRENCH.

(Application filed May 3, 1901..)

(No Model.)

UNITED STATES Prion.

" ATENT LAROY S. STARRETT, OF ATHOL, MASSACHUSETTS, ASSIGNOR TO THE L. S. STARRETT COMPANY, OF ATHOL, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

SCREW-WRENCH.

SPECIFICATION forming part of Letters Patent No. 716,303, dated December 16, 1902.

Application filed May 3, 1901. Serial No. 58,571. (No model.)

To all whom it may concern:

Be it known that I, LAROY S. STARRETT, of Athol, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Screw-Wrenches, of which the following is a specification.

The object of this invention is toimprove the various styles of screw-wrenches by taking up the looseness or backlash incidental to the wear as well as the loose fits usually allowed between the working parts, which gives much play to the movable jaw with relation to the head or fixed jaw. This looseness and backlash often require opening the jaws wider than is necessary to fit the work, because the loose member has moved too near thestationary one and must be moved back before it will go onto the nut. Thus time and patience are Wasted in resetting the jaws to fit the heads of bolts or nuts.

My improvement consists in providing the wrench with a spring serving to take up this looseness and forcing the movable jaw away from the fixed one, giving firmness to the working action of the wrench in taking up all slack or backlash. I make the screw and its enlarged milled head hollow and extend been applied, parts being shown in longitudinal section to show the construction.

A is the handle, B the shank, and-C the fixed head thereon.

D is the sliding jaw, recessed in its body to receive the actuating-screw E, the outer end of which turns in recesses in the shank and ferrule, as usual.

In embodying my invention, as herein shown, I form an axial perforation from end to end through the screw E and insert through it a spiral spring F, stretched to suitable tension and properly secured at each end, so as r to draw the jaw and screw E from the fixed head C. The ends of the wire spring are shown attached to jaw D by a headed stud G'and to a projection J on the ferrule bya cap II. This projection, as shown, is recessed suitably for the coils of the spring to pass through it, so that the spring may be re- .moved and a new one inserted when required,

the cap II being movable. With this construction a long spring is employed, which has increased efficiency by thus prolonging its coils through the head of screw E and the bearing therefor in the ferrule projection J. It will thus readily yield to the variations of tension incident to different adjustments of the jaw and not interfere with the operativeness of the wrench. The spring is also entirely concealed within the screw and movable jaw, where nothing can harm it, while the tool is lightened by making the screw tubular.

I claim as my invention- In a wrench, the handle, the shank and the fixed head, secured rigidly to each other, and the --movable jaw traversing said shank, in combination with the adjusting screw E formed with an enlarged axial recess extending from end to end thereof, the projection J on the handle-ferrule similarly recessed, and the retracting-spring F inclosed within said screw, its coils being adapted to pass through and work in the screw-head and its recessed bearing, substantially as set forth.

In testimony whereof I have affixed my signature in presence of two witnesses.

LAROY S. STARRETT.

\Vitnesses:

DAVID FINDLAY, FRANK E. WING. 

